DE-C-3,644,456 shows a projectile having an optically transparent window and a central spike.
US-A-4,500,051 shows a cannon launched projectile with a seeker comprising a gyro supported in an air bearing. The projectile has tail stabilizing fins and wings in its mid-portion, said wings being controlled by detector signals.
DE-A-3,438,544 shows an optical seeker comprising a Cassegrain system.
US-A-4,155,521 shows a cannon launched projectile with a gimbal suspended seeker and a gyro with an air bearing.
US-A-4,329,579 shows a target seeking device having a gimbal suspended rotor rotating about its axis with two degrees of freedom about a central point of rotation. The device includes a detector fixed with respect to the housing of the device, an optical system by which the field of view of the device is imaged in the plane of the detector, means for producing relative motion between the field of view image and the detector, a signal evaluating circuit, means for producing precession motion of the gyro rotor relative to the housing, and position sensors which respond to the angular position of the gyro rotor relative to the housing. A torquer is provided and receives scanning signals. The signals of the position sensors are applied to the torquer through a feedback loop. An evaluation circuit is provided for producing follow up signals from the detector signals and the position sensor signals.
The imaging optical system is a Cassegrain system. The tip of the missile is closed by a substantially spherical dome.
The geometrical axis of the gyro rotor itself executes a scanning motion. This is achieved by the scanning signals applied to the torquer. The position sensors provide the reaction of the gyro rotor to these scanning signals and are applied to a feedback loop. Thereby a well-defined scanning motion is achieved.
US-A-4,339,097 shows a target seeking head mounted in a dome of a missile. This target seeking head comprises a gyro rotor including a mid-portion forming a calotte-shaped peripheral surface. The convex calotte-shaped peripheral surface is surrounded substantially concentrically by a concave calotte-shaped bearing surface stationary with respect to the missile. A small gap is formed between the two surfaces. Pressurized gas is introduced into the gap to form a gas bearing centering the gyro. A target seeking scanning device comprises an annular parabolic mirror formed at the mid-portion of the gyro and a plane mirror imaging a field of view located at infinity in the plane of a detector mounted stationary with respect to the missile.
US-A-2,990,699 and GB-A-2,199,399 disclose cryostatic devices for cooling an infrared detector.
EP-B-0,192,125, US-A-4,039,246, US-A-4,009,393, EP-A-0,079,684 US-A-4,034,807 and US-A-4,413,177 disclose scanning devices with optically refracting, rotating wedge elements.